Fuel composition



United States Patent O FUEL COMPOSITION Stanley R. Newman and Robert Y.Heisler, Fishkill, and Norman Alpert, Poughkeepsie, N.Y., assignors toTexaco Inc., a corporation of Delaware No Drawing. Filed Nov. 8, 1957,Ser. No. 695,211

'3 Claims. c1. 44-69)- This invention relates to an improved internalcombustion engine fuel. More particularly it pertains to a leadedgasoline containing a specific polyhalogenated hydrocarbon additivewhich lowers the octane requirement increase and suppresses depositformation of the engine in which it is used.

Octane requirement increase (ORI) of internal combustion engines is awell known phenomenon in the art.

Briefly, it consists of a demand by a new motor for fuels havingincreasingly higher octane numbers in o'rder to exhibit knock-freeoperation. The demand for a higher octane fuel ceases when a so-calledpoint of equilibrium is reached at which point the quantity of depositformation remains substantially even and the octane requirement of theengine remains relatively constant.

The initial build-up of deposits in the combustion chamber'of the sparkignition engine may be at least partially caused by the use oforganiclead compounds in the fuel to increase the octane number thereof. Afterignition some of the lead may remain in the combustion chamber in theform of deleterious deposits which tend to promote surface ignition andincrease octane requirement of the engine.

Tetraethyl lead (TEL) is usually incorporated in present day gasolinefuels used commercially for public automotive consumption in amounts offrom about 2 to 3 ml. per gallon. Most so-called regular gasoline fuelsuse in the neighborhood of 2.5+ ml. of TEL per gal. The upper limit of 3ml. has been designated as the maximum presently allowable amount inautomotive fuels. Tetraethyl lead as supplied for automotive usecontains 1.0 theory ethylene chloride and about 0.5 theory ethylenebromide. One (1.0) theory, as stated above, designates the theoreticalamount of additive required to convert all the lead present in the fuelto the lead halide. These compounds are lead scavengers which serve toremove lead from the combustion chamber in the form of lead chloridesand bromides. The combined tetraethyl lead, ethylene chloride andbromide is usually referred to as the tetraethyl lead (TEL) fluid.

Many compounds, including certain polyhalogenated hydrocarbons, havebeen proposed as additives for leaded gasoline to lower octanerequirement increase. US. Patent No. 2,784,160 in particular disclosesthree compounds which when added to a gasoline containing tetraethyllead reduce the octane requirement of the engine. The polyhalogenatedhydrocarbons disclosed are l-bromo-l,1-dichloro 2,2,2 trifluoroethane(BrCl CCF 1,2-dibromo-l-chloro-1,2,2-trifluoroethane ful, the patenteesdisclosed the results of tests on other closely related polyhalogenatedhydrocarbons in gasoline which did not display any advantageous results.

2,937,932 Patented M 24, 1960 fuel composition for spark ignitionengines comprises a major amount of a hydrocarbon boiling within thegasoline range, tetraethyl lead and from0.1 to 1.0 theory based on thetetraethyl lead of 1,1-difluoro-2,2-dichloro- 1,2 dibro'mo ethane.

The preferred amount of l,1-difluoro-2,2 dichloro 1,2- dibromo-ethanewhich is used in the present invention is about 0.5 theory. One (1.0)theory designates thetheoretical amount of additive necessary to convertall the lead present in the fuel to the lead halide. Generally, theamount of this additive which is useful in terms of percent by weightbased on the total fuel containing from 0.1 to 3 mLper gal. oftetraethyl lead is from 0.0008 to 0.052 percent.

The base fuel in accordance with this invention is a hydrocarbon fuelboiling ,withinthe gasoline range. This includes straight run gasolines,alkylate, thermally and catalytically cracked gasolines, catalyticallyreformed and hydroformed gasolines and mixtures of these types withthemselves and other paraffinic, olefinic and aromatic hydrocarbons toform a suitable fuel.

Other conventional spark ignition motor fuel additives are used in thefuels of the invention to produce fuels suitable for present day highcompression, high speed engines, such additives include, rust andoxidation inhibitors, stabilizers, coloring agents, metal deactivatorsand gum inhibitors.

To demonstrate the very excellent ability of1,1-difluoro-2,2-dichloro-1,2-dibromoethane to reduce octane requirementincrease of a spark ignition engine, the following test procedure wasused:

LAUSON H-2 OCTANE' REQUIREMENT INCREASE (ORI) TEST PROCEDURE A modifiedModel-H4 Lauson engine, which is a single cylinder, liquid cooled, fourstroke spark ignition engine with a bore of 2% inches and a stroke of 2%inches giving a displacement of 14.89 cubic inches, was used. Poweroutput was rated at 4.3 HP. at 2400 r.p.m. Compression ratio of theengine was 6.521 using a modified head. The original flywheel magnetowas replaced with a Bendix-Scintilla magneto, Type GER-4R and coupled tothe forward end of the crankshaft to provide ignition. The engine wasalso coupled to a 3 HR induction motor to provide the load. Thefollowing test operating conditions were observed:

Test duration To equilibrium O.R. =approx. 200-300 hrs.

Speed, r.p.m 1750.

Load, B.H.P Approx. 2.1.

Spark advance, B.T.C 20.

Fuel flow rate, lbs./hr 1.6.

Air-fuel ratio 13.5:1.

Coolant temp., F 210.

Carburetor air temp., F 100.

Oil temp, F 175.

Example I Using the foregoing test procedure, the ORI of a premiumreference fuel comprising mainly fluid catalytically cracked stock andstraight run gasoline was developed. This fuel contained 2.9 mL/gall oftetraethyl lead fluid, and had an ASTM' research octane rating of 95.1.The reference fuel had API gravity of 56.8 and a boiling point rangebetween 103 and 390 F. It was negative in the Copper. Corrosion Test andhad an oxidation stability in theASTMJ test? or 840 minutes. Thisfuelalso' contained about 6 lbs. per 1000 bbs. of fuel ofN,N-disecondaryvbutyl-p-phenylenediamine, a gum inhibitor, about 1.2lbs. 'per' 1000 bbs. of fuel of N,N'-disaliey1id'ene-1,2-diaminopropane,a metal deactivator, and about 1.1 lbs. per 1000 bbs. of fuel oflecithin, a fuel stabilizer. The following table shows the datadeveloped during the test pro'cedure:

Table I cant. These exceptional results are made even more unexpectedwhen viewed in the light of the test results on the fuel compositioncontainingthe additiveof' the prior art (BrClFC-CF Br) which is known tohave an ORI reducing eflect. The ability of the additive of theinvention (BrF CCCl Br) to reduce ORI of the fuel appears to be about100 percent greater than the known prior art additive basis the testdata developed;

The compound of the invention also has a cleanliness efiect'on thetestengine. The following table demon strates this ability. These datawere developed during the tests reported in Example I.

Table II COMBUSTION AREA DEPOSITS IN LAUSON H-2 ENGINE ReferenceReference fuel fuel plus additive Obviously, many modifications andvariations of theinvention', as hereinbefore' set forth, may be madewithout departing from the spirit and scope thereof, and therefore onlysuch limitations should-be imposed-as are indicated in the appendedclaims.

We claim:

1. An improved spark ignition motor fuel comprising a major proportionof a hydrocarbon boiling within the gasoline range, tetraethyl lead, and1,l-difluoro-2,2-dichloro-1,2-dibromoethane in an amount sutlicient toreduce octane requirement increase.

2. An improved spark ignition motor fuel as described in claim 1containing 0.1 to 1.0 theoryl,1-difluoro-2,2-dichloro-1,2-dibromoethane. I

3. An improved spark ignition motor fuel as described in claim 1containing 0.1 to 3 ml. per gallon oftetraethyl lead.

References Cited in the file of this patent UNITED STATES PATENTS HerbstAug. 24, 1943 Blaker Mar. 5, 1957 OTHER REFERENCES

1. AN IMPROVED SPARK IGNITION MOTOR FUEL COMPRISING A MAJOR PROPORTIONOF A HYDROCARBON BOILING WITHIN THE GASOLINE RANGE, TETRAETHYL LEAD, AND1,1-DIFLUORO-2,2-DICHLORO-1,2-DIBROMOETHANE IN AN AMOUNT SUFFICIENT TOREDUCE OCTANE REQUIREMENT INCREASE.